mirror of
https://github.com/afska/gba-link-connection.git
synced 2026-03-21 17:44:21 -05:00
285 lines
6.8 KiB
C++
285 lines
6.8 KiB
C++
#ifndef LINK_PS2_KEYBOARD_H
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#define LINK_PS2_KEYBOARD_H
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// --------------------------------------------------------------------------
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// A PS/2 Keyboard Adapter for the GBA.
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// --------------------------------------------------------------------------
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// Usage:
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// - 1) Include this header in your main.cpp file and add:
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// LinkPS2Keyboard* linkPS2Keyboard = new LinkPS2Keyboard([](u8 event) {
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// // handle event (check example scan codes below)
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// });
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// - 2) Add the required interrupt service routines: (*)
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// irq_init(NULL);
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// irq_add(II_VBLANK, LINK_PS2_KEYBOARD_ISR_VBLANK);
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// irq_add(II_SERIAL, LINK_PS2_KEYBOARD_ISR_SERIAL);
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// - 3) Initialize the library with:
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// linkPS2Keyboard->activate();
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// - 4) Handle events in the callback sent to LinkPS2Keyboard's constructor!
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// --------------------------------------------------------------------------
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// (*1) libtonc's interrupt handler sometimes ignores interrupts due to a bug.
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// That causes packet loss. You REALLY want to use libugba's instead.
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// (see examples)
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// --------------------------------------------------------------------------
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// (*2) The hardware is very sensitive to timing. Make sure that
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// `LINK_PS2_KEYBOARD_ISR_SERIAL()` is handled on time. That means:
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// Be careful with DMA usage (which stops the CPU), and write short
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// interrupt handlers (or activate nested interrupts by setting
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// `REG_IME=1` at the start of your handlers).
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// --------------------------------------------------------------------------
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// ____________
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// | Pinout |
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// |PS/2 --- GBA|
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// |------------|
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// |CLOCK -> SI |
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// |DATA --> SO |
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// |VCC ---> VCC|
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// |GND ---> GND|
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// --------------------------------------------------------------------------
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#ifndef LINK_DEVELOPMENT
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#pragma GCC system_header
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#endif
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#include "_link_common.hpp"
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static volatile char LINK_PS2_KEYBOARD_VERSION[] = "LinkPS2Keyboard/v7.0.0";
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/**
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* @brief A PS/2 Keyboard Adapter for the GBA.
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*/
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class LinkPS2Keyboard {
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private:
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using u32 = unsigned int;
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using u16 = unsigned short;
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using u8 = unsigned char;
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static constexpr int RCNT_GPIO_AND_SI_IRQ = 0b1000000100000000;
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static constexpr int RCNT_GPIO = 0b1000000000000000;
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static constexpr int SI_DIRECTION = 0b1000000;
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static constexpr int SO_DIRECTION = 0b10000000;
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static constexpr int SI_DATA = 0b100;
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static constexpr int SO_DATA = 0b1000;
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static constexpr int TIMEOUT_FRAMES = 15; // (~250ms)
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LinkPS2Keyboard() = delete;
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public:
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using EventCallback = void (*)(u8 event);
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/**
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* @brief Constructs a new LinkPS2Keyboard object.
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* @param onEvent Function pointer that will receive the scan codes (`u8`).
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* Check out `LINK_PS2_KEYBOARD_KEY` and `LINK_PS2_KEYBOARD_EVENT` for codes.
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*/
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explicit LinkPS2Keyboard(EventCallback onEvent) { this->onEvent = onEvent; }
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/**
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* @brief Returns whether the library is active or not.
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*/
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[[nodiscard]] bool isActive() { return isEnabled; }
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/**
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* @brief Activates the library.
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*/
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void activate() {
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deactivate();
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Link::_REG_RCNT = RCNT_GPIO_AND_SI_IRQ;
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Link::_REG_SIOCNT = 0;
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bitcount = 0;
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incoming = 0;
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parityBit = 0;
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prevFrame = 0;
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frameCounter = 0;
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isEnabled = true;
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}
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/**
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* @brief Deactivates the library.
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*/
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void deactivate() {
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isEnabled = false;
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Link::_REG_RCNT = RCNT_GPIO;
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Link::_REG_SIOCNT = 0;
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}
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/**
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* @brief This method is called by the VBLANK interrupt handler.
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* \warning This is internal API!
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*/
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void _onVBlank() { frameCounter++; }
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/**
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* @brief This method is called by the SERIAL interrupt handler.
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* \warning This is internal API!
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*/
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void _onSerial() {
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if (!isEnabled)
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return;
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u8 val = (Link::_REG_RCNT & SO_DATA) != 0;
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u32 nowFrame = frameCounter;
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if (nowFrame - prevFrame > TIMEOUT_FRAMES) {
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bitcount = 0;
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incoming = 0;
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parityBit = 0;
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}
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prevFrame = nowFrame;
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if (bitcount == 0 && val == 0) { // start bit detected
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// start bit is always 0, so only proceed if val is 0
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bitcount++;
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} else if (bitcount >= 1 && bitcount <= 8) { // data bits
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incoming |= (val << (bitcount - 1));
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bitcount++;
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} else if (bitcount == 9) { // parity bit
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// store parity bit for later check
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parityBit = val;
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bitcount++;
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} else if (bitcount == 10) { // stop bit
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if (val == 1) { // stop bit should be 1
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// calculate parity (including the stored parity bit from previous IRQ)
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u8 parity = 0;
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for (u8 i = 0; i < 8; i++)
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parity += (incoming >> i) & 1;
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parity += parityBit;
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if (parity % 2 != 0) // odd parity as expected
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onEvent(incoming);
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}
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bitcount = 0;
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incoming = 0;
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parityBit = 0;
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}
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}
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private:
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bool isEnabled = false;
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u8 bitcount = 0;
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u8 incoming = 0;
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u8 parityBit = 0;
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u32 prevFrame = 0;
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u32 frameCounter = 0;
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EventCallback onEvent;
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};
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extern LinkPS2Keyboard* linkPS2Keyboard;
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/**
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* @brief VBLANK interrupt handler.
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*/
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inline void LINK_PS2_KEYBOARD_ISR_VBLANK() {
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if (!linkPS2Keyboard->isActive())
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return;
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linkPS2Keyboard->_onVBlank();
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}
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/**
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* @brief SERIAL interrupt handler.
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*/
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inline void LINK_PS2_KEYBOARD_ISR_SERIAL() {
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linkPS2Keyboard->_onSerial();
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}
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/**
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* @brief Key Scan Code list.
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*/
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enum LINK_PS2_KEYBOARD_KEY {
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ESC = 118,
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F1 = 5,
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F2 = 6,
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F3 = 4,
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F4 = 12,
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F5 = 3,
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F6 = 11,
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F7 = 131,
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F8 = 10,
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F9 = 1,
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F10 = 9,
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F11 = 120,
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F12 = 7,
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BACKSPACE = 102,
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TAB = 13,
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ENTER = 90,
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SHIFT_L = 18,
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SHIFT_R = 89,
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SUPER = 97,
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CTRL_L = 20,
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SPECIAL_CTRL_R = 224 + 20,
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ALT_L = 17,
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SPECIAL_ALT_R = 224 + 17,
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SPACE = 41,
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CAPS_LOCK = 88,
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NUM_LOCK = 119,
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SCROLL_LOCK = 126,
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SPECIAL_INSERT = 224 + 112,
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SPECIAL_DELETE = 224 + 113,
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SPECIAL_HOME = 224 + 108,
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SPECIAL_END = 224 + 105,
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SPECIAL_PAGE_UP = 224 + 125,
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SPECIAL_PAGE_DOWN = 224 + 122,
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SPECIAL_UP = 224 + 117,
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SPECIAL_DOWN = 224 + 114,
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SPECIAL_LEFT = 224 + 107,
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SPECIAL_RIGHT = 224 + 116,
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A = 28,
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B = 50,
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C = 33,
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D = 35,
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E = 36,
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F = 43,
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G = 52,
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H = 51,
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I = 67,
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J = 59,
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K = 66,
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L = 75,
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M = 58,
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N = 49,
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O = 68,
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P = 77,
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Q = 21,
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R = 45,
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S = 27,
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T = 44,
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U = 60,
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V = 42,
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W = 29,
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X = 34,
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Y = 53,
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Z = 26,
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NUMPAD_0 = 112,
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NUMPAD_1 = 105,
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NUMPAD_2 = 114,
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NUMPAD_3 = 122,
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NUMPAD_4 = 107,
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NUMPAD_5 = 115,
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NUMPAD_6 = 116,
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NUMPAD_7 = 108,
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NUMPAD_8 = 117,
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NUMPAD_9 = 125,
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NUMPAD_PLUS = 121,
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NUMPAD_MINUS = 123,
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SPECIAL_NUMPAD_ENTER = 224 + 90,
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NUMPAD_DOT = 113,
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NUMPAD_ASTERISK = 124,
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NUMPAD_SLASH = 74
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};
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/**
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* @brief Event Scan Code list.
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*/
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enum LINK_PS2_KEYBOARD_EVENT {
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SELF_TEST_PASSED = 0xAA, // Triggered when hot-plugging the keyboard
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RELEASE = 240, // Triggered before each key release
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SPECIAL = 224 // Triggered before special keys
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};
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#endif // LINK_PS2_KEYBOARD_H
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